X-linked hypophosphatemic rickets : the challenges of treatment

Abstract

X-linked dominant hypophosphatemic rickets (XLHR) is the most common inherited form of rickets due to a mutation in the phosphate regulating gene with homologies to endopeptidases on the X chromosome (PHEX gene) expressed in bones and teeth. This leads to impaired renal reabsorption of phosphate and defective bone mineralization. Clinical presentation often occurs in childhood, where children mostly present with bow legs, delayed walking, or gait difficulties. Other clinical features may also be present and these are described in this review in addition to the classic laboratory findings. Focus is made on the management of XLHR and its challenges, highlighting the complications that may arise from medical treatment with reference to literature. Moreover, we also describe novel treatment in XLHR; the potential use of growth hormone and cinacalcet, and the newly approved human monoclonal antibody against FGF-23 as a more targeted therapy.